"""DDL, table creation, and schema initialization."""

from __future__ import annotations

import sqlite3
from pathlib import Path

DDL = """
CREATE TABLE IF NOT EXISTS dimensions (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    name        TEXT UNIQUE NOT NULL,
    description TEXT
);

CREATE TABLE IF NOT EXISTS entities (
    id           INTEGER PRIMARY KEY AUTOINCREMENT,
    dimension_id INTEGER NOT NULL REFERENCES dimensions(id),
    name         TEXT NOT NULL,
    description  TEXT,
    UNIQUE(dimension_id, name)
);

CREATE TABLE IF NOT EXISTS dependencies (
    id              INTEGER PRIMARY KEY AUTOINCREMENT,
    entity_id       INTEGER NOT NULL REFERENCES entities(id),
    category        TEXT NOT NULL,
    key             TEXT NOT NULL,
    value           TEXT NOT NULL,
    unit            TEXT,
    constraint_type TEXT NOT NULL
);

CREATE TABLE IF NOT EXISTS domains (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    name        TEXT UNIQUE NOT NULL,
    description TEXT
);

CREATE TABLE IF NOT EXISTS metrics (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    name        TEXT UNIQUE NOT NULL,
    unit        TEXT,
    description TEXT
);

CREATE TABLE IF NOT EXISTS domain_metric_weights (
    id        INTEGER PRIMARY KEY AUTOINCREMENT,
    domain_id INTEGER NOT NULL REFERENCES domains(id),
    metric_id INTEGER NOT NULL REFERENCES metrics(id),
    weight    REAL NOT NULL,
    norm_min  REAL,
    norm_max  REAL,
    UNIQUE(domain_id, metric_id)
);

CREATE TABLE IF NOT EXISTS combinations (
    id           INTEGER PRIMARY KEY AUTOINCREMENT,
    hash         TEXT UNIQUE NOT NULL,
    status       TEXT NOT NULL DEFAULT 'pending',
    block_reason TEXT,
    created_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS combination_entities (
    combination_id INTEGER NOT NULL REFERENCES combinations(id),
    entity_id      INTEGER NOT NULL REFERENCES entities(id),
    PRIMARY KEY (combination_id, entity_id)
);

CREATE TABLE IF NOT EXISTS combination_scores (
    id                INTEGER PRIMARY KEY AUTOINCREMENT,
    combination_id    INTEGER NOT NULL REFERENCES combinations(id),
    domain_id         INTEGER NOT NULL REFERENCES domains(id),
    metric_id         INTEGER NOT NULL REFERENCES metrics(id),
    raw_value         REAL,
    normalized_score  REAL,
    estimation_method TEXT,
    confidence        REAL,
    UNIQUE(combination_id, domain_id, metric_id)
);

CREATE TABLE IF NOT EXISTS combination_results (
    id              INTEGER PRIMARY KEY AUTOINCREMENT,
    combination_id  INTEGER NOT NULL REFERENCES combinations(id),
    domain_id       INTEGER NOT NULL REFERENCES domains(id),
    composite_score REAL,
    novelty_flag    TEXT,
    llm_review      TEXT,
    human_notes     TEXT,
    pass_reached    INTEGER,
    UNIQUE(combination_id, domain_id)
);

CREATE TABLE IF NOT EXISTS pipeline_runs (
    id              INTEGER PRIMARY KEY AUTOINCREMENT,
    domain_id       INTEGER NOT NULL REFERENCES domains(id),
    status          TEXT NOT NULL DEFAULT 'pending',
    config          TEXT,
    total_combos    INTEGER DEFAULT 0,
    combos_pass1    INTEGER DEFAULT 0,
    combos_pass2    INTEGER DEFAULT 0,
    combos_pass3    INTEGER DEFAULT 0,
    combos_pass4    INTEGER DEFAULT 0,
    current_pass    INTEGER,
    error_message   TEXT,
    started_at      TIMESTAMP,
    completed_at    TIMESTAMP,
    created_at      TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE INDEX IF NOT EXISTS idx_deps_entity ON dependencies(entity_id);
CREATE INDEX IF NOT EXISTS idx_deps_category_key ON dependencies(category, key);
CREATE INDEX IF NOT EXISTS idx_combo_status ON combinations(status);
CREATE INDEX IF NOT EXISTS idx_scores_combo_domain ON combination_scores(combination_id, domain_id);
CREATE INDEX IF NOT EXISTS idx_results_domain_score ON combination_results(domain_id, composite_score DESC);
CREATE INDEX IF NOT EXISTS idx_pipeline_runs_domain ON pipeline_runs(domain_id);
"""


def init_db(db_path: str | Path) -> sqlite3.Connection:
    """Create/open the database and ensure all tables exist."""
    db_path = Path(db_path)
    db_path.parent.mkdir(parents=True, exist_ok=True)
    conn = sqlite3.connect(str(db_path))
    conn.execute("PRAGMA journal_mode=WAL")
    conn.execute("PRAGMA foreign_keys=ON")
    conn.executescript(DDL)
    conn.commit()
    return conn