"""Author: Sandeep Belgavi. Offline release gate, not a deployment controller."""
from dataclasses import dataclass, asdict
import hashlib
import json


@dataclass(frozen=True)
class Bundle:
    code: str
    prompt: str
    model: str
    tools: str
    schema: str

    def digest(self):
        if not all(isinstance(v, str) and v for v in asdict(self).values()):
            raise ValueError('Complete version bundle required')
        return hashlib.sha256(json.dumps(asdict(self), sort_keys=True).encode()).hexdigest()


class ReleaseGate:
    def __init__(self, baseline, candidate, percent=10):
        baseline.digest()
        candidate.digest()
        if baseline.schema != candidate.schema:
            raise ValueError('Schema compatibility requires separate migration review')
        if not 0 <= percent <= 100:
            raise ValueError('Invalid canary percentage')
        self.baseline, self.candidate, self.percent = baseline, candidate, percent
        self.active = baseline

    def cohort(self, tenant, incident):
        if not tenant or not incident:
            raise ValueError('Stable cohort identity required')
        key = json.dumps([tenant, incident], separators=(',', ':')).encode()
        bucket = int(hashlib.sha256(key).hexdigest(), 16) % 100
        return 'candidate' if bucket < self.percent else 'baseline'

    def assess(self, control_n, control_fail, candidate_n, candidate_fail, unauthorized=0, approved=False):
        values = (control_n, control_fail, candidate_n, candidate_fail, unauthorized)
        if any(not isinstance(v, int) or isinstance(v, bool) or v < 0 for v in values):
            raise ValueError('Nonnegative integer observations required')
        if control_fail > control_n or candidate_fail > candidate_n:
            raise ValueError('Failures exceed observations')
        if unauthorized:
            self.active = self.baseline
            return 'rollback'
        if min(control_n, candidate_n) < 20:
            return 'hold'
        if candidate_fail / candidate_n > control_fail / control_n + 0.10:
            self.active = self.baseline
            return 'rollback'
        if not approved:
            return 'await_approval'
        self.active = self.candidate
        return 'promote'


def main():
    base = Bundle('c1', 'p1', 'm1', 't1', 's1')
    candidate = Bundle('c2', 'p2', 'm1', 't1', 's1')
    gate = ReleaseGate(base, candidate)
    hold = gate.assess(100, 2, 5, 0)
    decision = gate.assess(100, 2, 20, 1, approved=True)
    rollback = gate.assess(100, 2, 20, 1, unauthorized=1)
    print(json.dumps({'hold': hold, 'decision': decision, 'rollback': rollback, 'active_code': gate.active.code}, sort_keys=True))


if __name__ == '__main__': main()