//! Tool definitions for file editing via LLM.

use serde::{Deserialize, Serialize};
use serde_json::json;

use crate::db::models::{BodyElement, ChartType};

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Tool {
    pub name: String,
    pub description: String,
    pub parameters: serde_json::Value,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ToolCall {
    pub id: String,
    pub name: String,
    pub arguments: serde_json::Value,
}

#[derive(Debug, Clone, Serialize, Deserialize, utoipa::ToSchema)]
pub struct ToolResult {
    pub success: bool,
    pub message: String,
}

/// Available tools for file editing
pub static AVAILABLE_TOOLS: once_cell::sync::Lazy<Vec<Tool>> =
    once_cell::sync::Lazy::new(|| {
        vec![
            Tool {
                name: "add_heading".to_string(),
                description: "Add a heading element to the file body".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {
                        "level": {
                            "type": "integer",
                            "description": "Heading level (1-6)",
                            "minimum": 1,
                            "maximum": 6
                        },
                        "text": {
                            "type": "string",
                            "description": "The heading text"
                        },
                        "position": {
                            "type": "integer",
                            "description": "Optional position to insert at (0-indexed). If not specified, appends to end."
                        }
                    },
                    "required": ["level", "text"]
                }),
            },
            Tool {
                name: "add_paragraph".to_string(),
                description: "Add a paragraph element to the file body".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {
                        "text": {
                            "type": "string",
                            "description": "The paragraph text"
                        },
                        "position": {
                            "type": "integer",
                            "description": "Optional position to insert at (0-indexed). If not specified, appends to end."
                        }
                    },
                    "required": ["text"]
                }),
            },
            Tool {
                name: "add_chart".to_string(),
                description: "Add a chart visualization to the file body. Supports line, bar, pie, and area charts.".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {
                        "chart_type": {
                            "type": "string",
                            "enum": ["line", "bar", "pie", "area"],
                            "description": "Type of chart to create"
                        },
                        "title": {
                            "type": "string",
                            "description": "Optional chart title"
                        },
                        "data": {
                            "type": "array",
                            "description": "Array of data points. Each point should have a 'name' field and one or more numeric value fields.",
                            "items": {
                                "type": "object"
                            }
                        },
                        "config": {
                            "type": "object",
                            "description": "Optional chart configuration (colors, axes, etc.)"
                        },
                        "position": {
                            "type": "integer",
                            "description": "Optional position to insert at (0-indexed). If not specified, appends to end."
                        }
                    },
                    "required": ["chart_type", "data"]
                }),
            },
            Tool {
                name: "remove_element".to_string(),
                description: "Remove an element from the file body by index".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {
                        "index": {
                            "type": "integer",
                            "description": "Index of element to remove (0-indexed)"
                        }
                    },
                    "required": ["index"]
                }),
            },
            Tool {
                name: "update_element".to_string(),
                description: "Update an existing element in the file body".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {
                        "index": {
                            "type": "integer",
                            "description": "Index of element to update (0-indexed)"
                        },
                        "element": {
                            "type": "object",
                            "description": "New element data. Must include 'type' field (heading, paragraph, chart)."
                        }
                    },
                    "required": ["index", "element"]
                }),
            },
            Tool {
                name: "reorder_elements".to_string(),
                description: "Move an element from one position to another".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {
                        "from_index": {
                            "type": "integer",
                            "description": "Current index of the element"
                        },
                        "to_index": {
                            "type": "integer",
                            "description": "New index for the element"
                        }
                    },
                    "required": ["from_index", "to_index"]
                }),
            },
            Tool {
                name: "set_summary".to_string(),
                description: "Set the file summary text".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {
                        "summary": {
                            "type": "string",
                            "description": "The summary text"
                        }
                    },
                    "required": ["summary"]
                }),
            },
            Tool {
                name: "parse_csv".to_string(),
                description: "Parse CSV data into JSON format suitable for charts".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {
                        "csv": {
                            "type": "string",
                            "description": "CSV data string with header row"
                        }
                    },
                    "required": ["csv"]
                }),
            },
            Tool {
                name: "clear_body".to_string(),
                description: "Clear all elements from the file body".to_string(),
                parameters: json!({
                    "type": "object",
                    "properties": {}
                }),
            },
        ]
    });

/// Result of executing a tool call with modified file state
#[derive(Debug)]
pub struct ToolExecutionResult {
    pub result: ToolResult,
    pub new_body: Option<Vec<BodyElement>>,
    pub new_summary: Option<String>,
    pub parsed_data: Option<serde_json::Value>,
}

/// Execute a tool call and return the result along with any state changes
pub fn execute_tool_call(
    call: &ToolCall,
    current_body: &[BodyElement],
    current_summary: Option<&str>,
) -> ToolExecutionResult {
    match call.name.as_str() {
        "add_heading" => execute_add_heading(call, current_body),
        "add_paragraph" => execute_add_paragraph(call, current_body),
        "add_chart" => execute_add_chart(call, current_body),
        "remove_element" => execute_remove_element(call, current_body),
        "update_element" => execute_update_element(call, current_body),
        "reorder_elements" => execute_reorder_elements(call, current_body),
        "set_summary" => execute_set_summary(call, current_summary),
        "parse_csv" => execute_parse_csv(call),
        "clear_body" => execute_clear_body(),
        _ => ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: format!("Unknown tool: {}", call.name),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        },
    }
}

fn execute_add_heading(call: &ToolCall, current_body: &[BodyElement]) -> ToolExecutionResult {
    let level = call.arguments.get("level").and_then(|v| v.as_u64()).unwrap_or(1) as u8;
    let text = call
        .arguments
        .get("text")
        .and_then(|v| v.as_str())
        .unwrap_or("")
        .to_string();
    let position = call.arguments.get("position").and_then(|v| v.as_u64());

    let element = BodyElement::Heading { level, text: text.clone() };
    let mut new_body = current_body.to_vec();

    if let Some(pos) = position {
        let pos = pos as usize;
        if pos <= new_body.len() {
            new_body.insert(pos, element);
        } else {
            new_body.push(element);
        }
    } else {
        new_body.push(element);
    }

    ToolExecutionResult {
        result: ToolResult {
            success: true,
            message: format!("Added heading: {}", text),
        },
        new_body: Some(new_body),
        new_summary: None,
        parsed_data: None,
    }
}

fn execute_add_paragraph(call: &ToolCall, current_body: &[BodyElement]) -> ToolExecutionResult {
    let text = call
        .arguments
        .get("text")
        .and_then(|v| v.as_str())
        .unwrap_or("")
        .to_string();
    let position = call.arguments.get("position").and_then(|v| v.as_u64());

    let element = BodyElement::Paragraph { text: text.clone() };
    let mut new_body = current_body.to_vec();

    if let Some(pos) = position {
        let pos = pos as usize;
        if pos <= new_body.len() {
            new_body.insert(pos, element);
        } else {
            new_body.push(element);
        }
    } else {
        new_body.push(element);
    }

    let preview = if text.len() > 50 {
        format!("{}...", &text[..50])
    } else {
        text
    };

    ToolExecutionResult {
        result: ToolResult {
            success: true,
            message: format!("Added paragraph: {}", preview),
        },
        new_body: Some(new_body),
        new_summary: None,
        parsed_data: None,
    }
}

fn execute_add_chart(call: &ToolCall, current_body: &[BodyElement]) -> ToolExecutionResult {
    let chart_type_str = call
        .arguments
        .get("chart_type")
        .and_then(|v| v.as_str())
        .unwrap_or("bar");

    let chart_type = match chart_type_str {
        "line" => ChartType::Line,
        "bar" => ChartType::Bar,
        "pie" => ChartType::Pie,
        "area" => ChartType::Area,
        _ => ChartType::Bar,
    };

    let title = call
        .arguments
        .get("title")
        .and_then(|v| v.as_str())
        .map(|s| s.to_string());

    let data = call
        .arguments
        .get("data")
        .cloned()
        .unwrap_or(json!([]));

    let config = call.arguments.get("config").cloned();
    let position = call.arguments.get("position").and_then(|v| v.as_u64());

    let element = BodyElement::Chart {
        chart_type,
        title: title.clone(),
        data,
        config,
    };

    let mut new_body = current_body.to_vec();

    if let Some(pos) = position {
        let pos = pos as usize;
        if pos <= new_body.len() {
            new_body.insert(pos, element);
        } else {
            new_body.push(element);
        }
    } else {
        new_body.push(element);
    }

    ToolExecutionResult {
        result: ToolResult {
            success: true,
            message: format!(
                "Added {} chart{}",
                chart_type_str,
                title.map(|t| format!(": {}", t)).unwrap_or_default()
            ),
        },
        new_body: Some(new_body),
        new_summary: None,
        parsed_data: None,
    }
}

fn execute_remove_element(call: &ToolCall, current_body: &[BodyElement]) -> ToolExecutionResult {
    let index = call.arguments.get("index").and_then(|v| v.as_u64());

    let Some(index) = index else {
        return ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: "Missing index parameter".to_string(),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        };
    };

    let index = index as usize;
    if index >= current_body.len() {
        return ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: format!("Index {} out of bounds (body has {} elements)", index, current_body.len()),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        };
    }

    let mut new_body = current_body.to_vec();
    new_body.remove(index);

    ToolExecutionResult {
        result: ToolResult {
            success: true,
            message: format!("Removed element at index {}", index),
        },
        new_body: Some(new_body),
        new_summary: None,
        parsed_data: None,
    }
}

fn execute_update_element(call: &ToolCall, current_body: &[BodyElement]) -> ToolExecutionResult {
    let index = call.arguments.get("index").and_then(|v| v.as_u64());
    let element_json = call.arguments.get("element");

    let Some(index) = index else {
        return ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: "Missing index parameter".to_string(),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        };
    };

    let Some(element_json) = element_json else {
        return ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: "Missing element parameter".to_string(),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        };
    };

    let index = index as usize;
    if index >= current_body.len() {
        return ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: format!("Index {} out of bounds (body has {} elements)", index, current_body.len()),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        };
    }

    let new_element: Result<BodyElement, _> = serde_json::from_value(element_json.clone());
    match new_element {
        Ok(element) => {
            let mut new_body = current_body.to_vec();
            new_body[index] = element;

            ToolExecutionResult {
                result: ToolResult {
                    success: true,
                    message: format!("Updated element at index {}", index),
                },
                new_body: Some(new_body),
                new_summary: None,
                parsed_data: None,
            }
        }
        Err(e) => ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: format!("Invalid element format: {}", e),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        },
    }
}

fn execute_reorder_elements(call: &ToolCall, current_body: &[BodyElement]) -> ToolExecutionResult {
    let from_index = call.arguments.get("from_index").and_then(|v| v.as_u64());
    let to_index = call.arguments.get("to_index").and_then(|v| v.as_u64());

    let (Some(from), Some(to)) = (from_index, to_index) else {
        return ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: "Missing from_index or to_index parameter".to_string(),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        };
    };

    let from = from as usize;
    let to = to as usize;

    if from >= current_body.len() || to >= current_body.len() {
        return ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: format!(
                    "Index out of bounds: from={}, to={}, body has {} elements",
                    from, to, current_body.len()
                ),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        };
    }

    let mut new_body = current_body.to_vec();
    let element = new_body.remove(from);
    new_body.insert(to, element);

    ToolExecutionResult {
        result: ToolResult {
            success: true,
            message: format!("Moved element from index {} to {}", from, to),
        },
        new_body: Some(new_body),
        new_summary: None,
        parsed_data: None,
    }
}

fn execute_set_summary(call: &ToolCall, _current_summary: Option<&str>) -> ToolExecutionResult {
    let summary = call
        .arguments
        .get("summary")
        .and_then(|v| v.as_str())
        .unwrap_or("")
        .to_string();

    ToolExecutionResult {
        result: ToolResult {
            success: true,
            message: "Summary updated".to_string(),
        },
        new_body: None,
        new_summary: Some(summary),
        parsed_data: None,
    }
}

fn execute_parse_csv(call: &ToolCall) -> ToolExecutionResult {
    let csv = call
        .arguments
        .get("csv")
        .and_then(|v| v.as_str())
        .unwrap_or("");

    let lines: Vec<&str> = csv.lines().collect();
    if lines.is_empty() {
        return ToolExecutionResult {
            result: ToolResult {
                success: false,
                message: "Empty CSV data".to_string(),
            },
            new_body: None,
            new_summary: None,
            parsed_data: None,
        };
    }

    let headers: Vec<&str> = lines[0].split(',').map(|s| s.trim()).collect();
    let mut data: Vec<serde_json::Value> = Vec::new();

    for line in lines.iter().skip(1) {
        if line.trim().is_empty() {
            continue;
        }
        let values: Vec<&str> = line.split(',').map(|s| s.trim()).collect();
        let mut row = serde_json::Map::new();

        for (i, header) in headers.iter().enumerate() {
            if let Some(value) = values.get(i) {
                // Try to parse as number, otherwise use string
                if let Ok(num) = value.parse::<f64>() {
                    row.insert(header.to_string(), json!(num));
                } else {
                    row.insert(header.to_string(), json!(value));
                }
            }
        }

        data.push(serde_json::Value::Object(row));
    }

    ToolExecutionResult {
        result: ToolResult {
            success: true,
            message: format!("Parsed {} rows from CSV", data.len()),
        },
        new_body: None,
        new_summary: None,
        parsed_data: Some(json!(data)),
    }
}

fn execute_clear_body() -> ToolExecutionResult {
    ToolExecutionResult {
        result: ToolResult {
            success: true,
            message: "Cleared all body elements".to_string(),
        },
        new_body: Some(vec![]),
        new_summary: None,
        parsed_data: None,
    }
}