"""CSV and JSON export endpoints.

This module provides API endpoints for exporting session data
and analysis results in various formats.
"""

from __future__ import annotations

from typing import Literal

from fastapi import APIRouter, Query
from fastapi.responses import StreamingResponse
from pydantic import BaseModel, Field

router = APIRouter()


class ExportRequest(BaseModel):
    """Request for data export.

    Attributes
    ----------
    session_ids
        List of session identifiers to export. If empty, exports all sessions.
    include_keystrokes
        Whether to include raw keystroke data.
    include_metrics
        Whether to include computed metrics.
    include_verdicts
        Whether to include analysis verdicts.
    """

    session_ids: list[str] = Field(default_factory=list, description="Sessions to export")
    include_keystrokes: bool = Field(default=False, description="Include keystroke data")
    include_metrics: bool = Field(default=True, description="Include computed metrics")
    include_verdicts: bool = Field(default=True, description="Include verdicts")


class ExportStatus(BaseModel):
    """Status of an export task.

    Attributes
    ----------
    task_id
        Identifier for the export task.
    status
        Current status (pending, processing, completed, failed).
    progress
        Progress percentage from 0 to 100.
    download_url
        URL to download the completed export.
    error_message
        Error message if export failed.
    """

    task_id: str = Field(description="Export task identifier")
    status: str = Field(description="Task status")
    progress: int = Field(ge=0, le=100, description="Progress percentage")
    download_url: str | None = Field(default=None, description="Download URL")
    error_message: str | None = Field(default=None, description="Error message")


@router.get("/sessions/csv")
async def export_sessions_csv(
    session_ids: str | None = Query(default=None, description="Comma-separated session IDs"),
    include_verdicts: bool = Query(default=True, description="Include verdict columns"),
) -> StreamingResponse:
    """Export sessions as CSV.

    Exports session data as a CSV file with one row per session.
    Includes metadata, trial counts, and optionally verdict information.

    Parameters
    ----------
    session_ids
        Comma-separated list of session IDs to export. If not provided,
        exports all sessions.
    include_verdicts
        Whether to include verdict columns in the export.

    Returns
    -------
    StreamingResponse
        CSV file download response.
    """
    # TODO: Implement with storage service
    _ = (session_ids, include_verdicts)  # Suppress unused variable warning

    content = b"session_id,created_at,trial_count,verdict\n"

    return StreamingResponse(
        content=iter([content]),
        media_type="text/csv",
        headers={"Content-Disposition": "attachment; filename=sessions.csv"},
    )


@router.get("/trials/csv")
async def export_trials_csv(
    session_ids: str | None = Query(default=None, description="Comma-separated session IDs"),
    include_metrics: bool = Query(default=True, description="Include metric columns"),
) -> StreamingResponse:
    """Export trials as CSV.

    Exports trial data as a CSV file with one row per trial.
    Includes response text length, keystroke counts, and optionally
    computed metrics.

    Parameters
    ----------
    session_ids
        Comma-separated list of session IDs to export trials from.
        If not provided, exports trials from all sessions.
    include_metrics
        Whether to include metric columns in the export.

    Returns
    -------
    StreamingResponse
        CSV file download response.
    """
    # TODO: Implement with storage service
    _ = (session_ids, include_metrics)  # Suppress unused variable warning

    content = b"session_id,trial_index,trial_type,response_length,keystroke_count\n"

    return StreamingResponse(
        content=iter([content]),
        media_type="text/csv",
        headers={"Content-Disposition": "attachment; filename=trials.csv"},
    )


@router.get("/keystrokes/csv")
async def export_keystrokes_csv(
    session_id: str = Query(description="Session ID to export"),
    trial_index: int | None = Query(default=None, description="Trial index to export"),
) -> StreamingResponse:
    """Export keystroke data as CSV.

    Exports raw keystroke events as a CSV file. Due to the potentially
    large size of keystroke data, this endpoint requires a session ID
    and optionally a trial index.

    Parameters
    ----------
    session_id
        Session ID to export keystrokes from.
    trial_index
        Specific trial index to export. If not provided, exports
        keystrokes from all trials in the session.

    Returns
    -------
    StreamingResponse
        CSV file download response.
    """
    # TODO: Implement with storage service
    _ = trial_index  # Suppress unused variable warning

    content = b"session_id,trial_index,time,key,code,event\n"

    return StreamingResponse(
        content=iter([content]),
        media_type="text/csv",
        headers={"Content-Disposition": f"attachment; filename=keystrokes_{session_id}.csv"},
    )


@router.get("/verdicts/csv")
async def export_verdicts_csv(
    verdict_filter: Literal["all", "human", "ai_assisted", "uncertain"] = Query(
        default="all", description="Filter by verdict type"
    ),
    min_confidence: float = Query(default=0.0, ge=0.0, le=1.0, description="Minimum confidence"),
) -> StreamingResponse:
    """Export verdicts as CSV.

    Exports analysis verdicts as a CSV file with one row per session.
    Includes verdict type, confidence score, and flag counts.

    Parameters
    ----------
    verdict_filter
        Filter by verdict type. Use "all" to include all verdicts.
    min_confidence
        Minimum confidence score to include.

    Returns
    -------
    StreamingResponse
        CSV file download response.
    """
    # TODO: Implement with storage service
    _ = (verdict_filter, min_confidence)  # Suppress unused variable warning

    content = b"session_id,verdict,confidence,flag_count,analyzed_at\n"

    return StreamingResponse(
        content=iter([content]),
        media_type="text/csv",
        headers={"Content-Disposition": "attachment; filename=verdicts.csv"},
    )


@router.post("/json")
async def export_json(request: ExportRequest) -> dict[str, str]:
    """Export data as JSON.

    Starts a background task to export session data as a JSON file.
    Use the returned task_id to check status and download the result.

    Parameters
    ----------
    request
        Export configuration specifying sessions and data to include.

    Returns
    -------
    dict[str, str]
        Task ID for the background export job.
    """
    # TODO: Implement with background task queue
    _ = request  # Suppress unused variable warning
    return {"task_id": "not-implemented", "status": "pending"}


@router.get("/status/{task_id}", response_model=ExportStatus)
async def get_export_status(task_id: str) -> ExportStatus:
    """Get status of an export task.

    Retrieves the current status and progress of a background
    export task.

    Parameters
    ----------
    task_id
        Identifier of the export task.

    Returns
    -------
    ExportStatus
        Task status with progress and download URL.
    """
    # TODO: Implement with background task queue
    return ExportStatus(
        task_id=task_id,
        status="not_found",
        progress=0,
        download_url=None,
        error_message="Export task system not implemented",
    )
