"""
Unified Prompt Executor (Issue #28 Phase 2)

Executes both base and pipeline-type prompts with:
- Dynamic placeholder resolution
- JSON output validation
- Multi-stage parallel execution
- Reference and inline prompt support
"""
import json
import re
from typing import Dict, Any, Optional
from db import get_db, get_cursor, r2d
from fastapi import HTTPException


def resolve_placeholders(template: str, variables: Dict[str, Any]) -> str:
    """
    Replace {{placeholder}} with values from variables dict.

    Args:
        template: String with {{key}} placeholders
        variables: Dict of key -> value mappings

    Returns:
        Template with placeholders replaced
    """
    def replacer(match):
        key = match.group(1).strip()
        if key in variables:
            value = variables[key]
            # Convert dict/list to JSON string
            if isinstance(value, (dict, list)):
                return json.dumps(value, ensure_ascii=False)
            return str(value)
        # Keep placeholder if no value found
        return match.group(0)

    return re.sub(r'\{\{([^}]+)\}\}', replacer, template)


def validate_json_output(output: str, schema: Optional[Dict] = None) -> Dict:
    """
    Validate that output is valid JSON.

    Args:
        output: String to validate
        schema: Optional JSON schema to validate against (TODO: jsonschema library)

    Returns:
        Parsed JSON dict

    Raises:
        HTTPException: If output is not valid JSON
    """
    try:
        parsed = json.loads(output)
        # TODO: Add jsonschema validation if schema provided
        return parsed
    except json.JSONDecodeError as e:
        raise HTTPException(
            status_code=500,
            detail=f"AI returned invalid JSON: {str(e)}"
        )


async def execute_prompt(
    prompt_slug: str,
    variables: Dict[str, Any],
    openrouter_call_func
) -> Dict[str, Any]:
    """
    Execute a single prompt (base or pipeline type).

    Args:
        prompt_slug: Slug of prompt to execute
        variables: Dict of variables for placeholder replacement
        openrouter_call_func: Async function(prompt_text) -> response_text

    Returns:
        Dict with execution results:
        {
            "type": "base" | "pipeline",
            "slug": "...",
            "output": "..." | {...},  # String or parsed JSON
            "stages": [...]  # Only for pipeline type
        }
    """
    # Load prompt from database
    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute(
            """SELECT * FROM ai_prompts
               WHERE slug = %s AND active = true""",
            (prompt_slug,)
        )
        row = cur.fetchone()
        if not row:
            raise HTTPException(404, f"Prompt nicht gefunden: {prompt_slug}")

        prompt = r2d(row)

    prompt_type = prompt.get('type', 'pipeline')

    if prompt_type == 'base':
        # Base prompt: single execution with template
        return await execute_base_prompt(prompt, variables, openrouter_call_func)

    elif prompt_type == 'pipeline':
        # Pipeline prompt: multi-stage execution
        return await execute_pipeline_prompt(prompt, variables, openrouter_call_func)

    else:
        raise HTTPException(400, f"Unknown prompt type: {prompt_type}")


async def execute_base_prompt(
    prompt: Dict,
    variables: Dict[str, Any],
    openrouter_call_func
) -> Dict[str, Any]:
    """Execute a base-type prompt (single template)."""
    template = prompt.get('template')
    if not template:
        raise HTTPException(400, f"Base prompt missing template: {prompt['slug']}")

    # Resolve placeholders
    prompt_text = resolve_placeholders(template, variables)

    # Call AI
    response = await openrouter_call_func(prompt_text)

    # Validate JSON if required
    output_format = prompt.get('output_format', 'text')
    if output_format == 'json':
        output = validate_json_output(response, prompt.get('output_schema'))
    else:
        output = response

    return {
        "type": "base",
        "slug": prompt['slug'],
        "output": output,
        "output_format": output_format
    }


async def execute_pipeline_prompt(
    prompt: Dict,
    variables: Dict[str, Any],
    openrouter_call_func
) -> Dict[str, Any]:
    """
    Execute a pipeline-type prompt (multi-stage).

    Each stage's results are added to variables for next stage.
    """
    stages = prompt.get('stages')
    if not stages:
        raise HTTPException(400, f"Pipeline prompt missing stages: {prompt['slug']}")

    # Parse stages if stored as JSON string
    if isinstance(stages, str):
        stages = json.loads(stages)

    stage_results = []
    context_vars = variables.copy()

    # Execute stages in order
    for stage_def in sorted(stages, key=lambda s: s['stage']):
        stage_num = stage_def['stage']
        stage_prompts = stage_def.get('prompts', [])

        if not stage_prompts:
            continue

        # Execute all prompts in this stage (parallel concept, sequential impl for now)
        stage_outputs = {}

        for prompt_def in stage_prompts:
            source = prompt_def.get('source')
            output_key = prompt_def.get('output_key', f'stage{stage_num}')
            output_format = prompt_def.get('output_format', 'text')

            if source == 'reference':
                # Reference to another prompt
                ref_slug = prompt_def.get('slug')
                if not ref_slug:
                    raise HTTPException(400, f"Reference prompt missing slug in stage {stage_num}")

                # Load referenced prompt
                result = await execute_prompt(ref_slug, context_vars, openrouter_call_func)
                output = result['output']

            elif source == 'inline':
                # Inline template
                template = prompt_def.get('template')
                if not template:
                    raise HTTPException(400, f"Inline prompt missing template in stage {stage_num}")

                prompt_text = resolve_placeholders(template, context_vars)
                response = await openrouter_call_func(prompt_text)

                # Validate JSON if required
                if output_format == 'json':
                    output = validate_json_output(response, prompt_def.get('output_schema'))
                else:
                    output = response

            else:
                raise HTTPException(400, f"Unknown prompt source: {source}")

            # Store output with key
            stage_outputs[output_key] = output

            # Add to context for next stage
            context_vars[f'stage_{stage_num}_{output_key}'] = output

        stage_results.append({
            "stage": stage_num,
            "outputs": stage_outputs
        })

    # Final output is last stage's first output
    final_output = stage_results[-1]['outputs'] if stage_results else {}

    return {
        "type": "pipeline",
        "slug": prompt['slug'],
        "stages": stage_results,
        "output": final_output,
        "output_format": prompt.get('output_format', 'text')
    }


async def execute_prompt_with_data(
    prompt_slug: str,
    profile_id: str,
    modules: Optional[Dict[str, bool]] = None,
    timeframes: Optional[Dict[str, int]] = None,
    openrouter_call_func = None
) -> Dict[str, Any]:
    """
    Execute prompt with data loaded from database.

    Args:
        prompt_slug: Slug of prompt to execute
        profile_id: User profile ID
        modules: Dict of module -> enabled (e.g., {"körper": true})
        timeframes: Dict of module -> days (e.g., {"körper": 30})
        openrouter_call_func: Async function for AI calls

    Returns:
        Execution result dict
    """
    from datetime import datetime, timedelta

    # Build variables from data modules
    variables = {
        'profile_id': profile_id,
        'today': datetime.now().strftime('%Y-%m-%d')
    }

    # Load data for enabled modules
    if modules:
        with get_db() as conn:
            cur = get_cursor(conn)

            # Weight data
            if modules.get('körper'):
                days = timeframes.get('körper', 30)
                since = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
                cur.execute(
                    """SELECT date, weight FROM weight_log
                       WHERE profile_id = %s AND date >= %s
                       ORDER BY date DESC""",
                    (profile_id, since)
                )
                variables['weight_data'] = [r2d(r) for r in cur.fetchall()]

            # Nutrition data
            if modules.get('ernährung'):
                days = timeframes.get('ernährung', 30)
                since = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
                cur.execute(
                    """SELECT date, kcal, protein_g, fat_g, carbs_g
                       FROM nutrition_log
                       WHERE profile_id = %s AND date >= %s
                       ORDER BY date DESC""",
                    (profile_id, since)
                )
                variables['nutrition_data'] = [r2d(r) for r in cur.fetchall()]

            # Activity data
            if modules.get('training'):
                days = timeframes.get('training', 14)
                since = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
                cur.execute(
                    """SELECT date, activity_type, duration_min, kcal_active, hr_avg
                       FROM activity_log
                       WHERE profile_id = %s AND date >= %s
                       ORDER BY date DESC""",
                    (profile_id, since)
                )
                variables['activity_data'] = [r2d(r) for r in cur.fetchall()]

            # Sleep data
            if modules.get('schlaf'):
                days = timeframes.get('schlaf', 14)
                since = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
                cur.execute(
                    """SELECT date, sleep_segments, source
                       FROM sleep_log
                       WHERE profile_id = %s AND date >= %s
                       ORDER BY date DESC""",
                    (profile_id, since)
                )
                variables['sleep_data'] = [r2d(r) for r in cur.fetchall()]

            # Vitals data
            if modules.get('vitalwerte'):
                days = timeframes.get('vitalwerte', 7)
                since = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')

                # Baseline vitals
                cur.execute(
                    """SELECT date, resting_hr, hrv, vo2_max, spo2, respiratory_rate
                       FROM vitals_baseline
                       WHERE profile_id = %s AND date >= %s
                       ORDER BY date DESC""",
                    (profile_id, since)
                )
                variables['vitals_baseline'] = [r2d(r) for r in cur.fetchall()]

                # Blood pressure
                cur.execute(
                    """SELECT measured_at, systolic, diastolic, pulse
                       FROM blood_pressure_log
                       WHERE profile_id = %s AND measured_at >= %s
                       ORDER BY measured_at DESC""",
                    (profile_id, since + ' 00:00:00')
                )
                variables['blood_pressure'] = [r2d(r) for r in cur.fetchall()]

            # Mental/Goals (no timeframe, just current state)
            if modules.get('mentales') or modules.get('ziele'):
                # TODO: Add mental state / goals data when implemented
                variables['goals_data'] = []

    # Execute prompt
    return await execute_prompt(prompt_slug, variables, openrouter_call_func)