#!/usr/bin/env bash

# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0

set -euo pipefail

REAL_GH="${OPENSHELL_REAL_GH:-/usr/bin/gh}"
GATOR_MARKER='> **gator-agent**'
GATOR_PAYLOAD_VERSION="${OPENSHELL_AGENT_PAYLOAD_VERSION:-5}"

if [[ $# -lt 1 || "$1" != "api" ]]; then
    exec "$REAL_GH" "$@"
fi

method="GET"
input_file=""
body_field=""
endpoint=""
args=("$@")

consume_next=false
for ((i = 1; i < ${#args[@]}; i++)); do
    arg="${args[$i]}"

    if [[ "$consume_next" == "true" ]]; then
        consume_next=false
        continue
    fi

    case "$arg" in
        --method|-X)
            if (( i + 1 < ${#args[@]} )); then
                method="${args[$((i + 1))]}"
                consume_next=true
            fi
            ;;
        --method=*)
            method="${arg#--method=}"
            ;;
        --input)
            if (( i + 1 < ${#args[@]} )); then
                input_file="${args[$((i + 1))]}"
                consume_next=true
            fi
            ;;
        --input=*)
            input_file="${arg#--input=}"
            ;;
        -f|--field|-F|--raw-field)
            if (( i + 1 < ${#args[@]} )); then
                field="${args[$((i + 1))]}"
                if [[ "$field" == body=* ]]; then
                    body_field="${field#body=}"
                fi
                consume_next=true
            fi
            ;;
        -fbody=*|--field=body=*|-Fbody=*|--raw-field=body=*)
            body_field="${arg#*=body=}"
            ;;
        --*)
            ;;
        *)
            if [[ -z "$endpoint" ]]; then
                endpoint="${arg#/}"
            fi
            ;;
    esac
done

read_body() {
    if [[ -n "$input_file" && -f "$input_file" ]]; then
        jq -r '.body // empty' "$input_file" 2>/dev/null || true
        return
    fi
    printf '%s' "$body_field"
}

is_legacy_reviewer_failure_disposition() {
    local existing_body="$1"
    local head_sha="$2"

    [[ "$existing_body" == *"$GATOR_MARKER"* ]] || return 1
    [[ "$existing_body" == *"$head_sha"* ]] || return 1
    [[ "$existing_body" == *"principal-engineer-reviewer"* ]] || return 1
    [[ "$existing_body" == *"failed before producing"* ]] || return 1
}

is_draft_only_blocker_disposition() {
    local existing_body="$1"
    local head_sha="$2"
    local lower_body

    [[ "$existing_body" == *"$GATOR_MARKER"* ]] || return 1
    [[ "$existing_body" == *"$head_sha"* ]] || return 1

    lower_body="$(printf '%s' "$existing_body" | tr '[:upper:]' '[:lower:]')"
    [[ "$lower_body" == *"## blocked"* ]] || return 1
    [[ "$lower_body" == *"marked as a draft"* || "$lower_body" == *"pull request is a draft"* || "$lower_body" == *"pr is draft"* ]] || return 1
}

is_ttl_state_nudge() {
    local body="$1"

    [[ "$body" == *"$GATOR_MARKER"* ]] || return 1
    [[ "$body" == *"more than 48 business hours"* ]] || return 1

    case "$body" in
        *"## Author Follow-Up Nudge"*|*"## Maintainer Review Nudge"*|*"## Merge Decision Nudge"*|*"## Blocker Follow-Up Nudge"*)
            return 0
            ;;
        *)
            return 1
            ;;
    esac
}

has_blocking_same_sha_disposition() {
    local head_sha="$1"
    local current_is_draft="$2"
    local encoded_bodies="$3"
    local encoded_body existing_body

    while IFS= read -r encoded_body; do
        [[ -n "$encoded_body" ]] || continue

        existing_body="$(printf '%s' "$encoded_body" | jq -r . 2>/dev/null || printf '%s' "$encoded_body")"
        [[ "$existing_body" == *"$head_sha"* ]] || continue

        if is_legacy_reviewer_failure_disposition "$existing_body" "$head_sha"; then
            continue
        fi

        if [[ "$current_is_draft" != "true" ]] && is_draft_only_blocker_disposition "$existing_body" "$head_sha"; then
            continue
        fi

        return 0
    done <<< "$encoded_bodies"

    return 1
}

guard_duplicate_gator_disposition() {
    local owner="$1"
    local repo="$2"
    local number="$3"
    local body="$4"

    [[ "$body" == *"$GATOR_MARKER"* ]] || return 0
    [[ "$body" != *"## Monitoring Complete"* ]] || return 0

    # A TTL state nudge is not a review disposition. Its frequency and target
    # are governed by the gator skill; allow it to keep an unchanged PR moving.
    is_ttl_state_nudge "$body" && return 0

    local pull_json head_sha current_is_draft
    if ! pull_json="$($REAL_GH api "repos/$owner/$repo/pulls/$number" 2>/dev/null)"; then
        echo "openshell-agent: blocked gator write because current PR head lookup failed for $owner/$repo#$number" >&2
        return 21
    fi
    head_sha="$(printf '%s' "$pull_json" | jq -r '.head.sha // empty' 2>/dev/null || true)"
    current_is_draft="$(printf '%s' "$pull_json" | jq -r '.draft // false' 2>/dev/null || true)"
    if [[ -z "$head_sha" ]]; then
        echo "openshell-agent: blocked gator write because current PR head was missing for $owner/$repo#$number" >&2
        return 21
    fi

    if is_legacy_reviewer_failure_disposition "$body" "$head_sha"; then
        echo "openshell-agent: blocked public reviewer sub-agent failure disposition for $owner/$repo#$number ($head_sha)" >&2
        echo "openshell-agent: return OPENSHELL_AGENT_RESULT status=transient_failure with reason=reviewer_subagent_failed instead" >&2
        return 20
    fi

    local existing_comments existing_reviews
    if ! existing_comments="$($REAL_GH api "repos/$owner/$repo/issues/$number/comments" --paginate --jq '.[] | select(.body | contains("> **gator-agent**")) | .body | @json' 2>/dev/null)"; then
        echo "openshell-agent: blocked gator write because existing comment lookup failed for $owner/$repo#$number" >&2
        return 21
    fi
    if ! existing_reviews="$($REAL_GH api "repos/$owner/$repo/pulls/$number/reviews" --paginate --jq '.[] | select(.body | contains("> **gator-agent**")) | .body | @json' 2>/dev/null)"; then
        echo "openshell-agent: blocked gator write because existing review lookup failed for $owner/$repo#$number" >&2
        return 21
    fi

    if has_blocking_same_sha_disposition "$head_sha" "$current_is_draft" "$(printf '%s\n%s\n' "$existing_comments" "$existing_reviews")"; then
        echo "openshell-agent: blocked duplicate gator same-SHA disposition for $owner/$repo#$number ($head_sha)" >&2
        echo "openshell-agent: push a new commit, remove the old disposition, or set OPENSHELL_GATOR_ALLOW_SAME_SHA_COMMENT=1 for an explicit maintainer-requested same-SHA action" >&2
        return 20
    fi

    if [[ "$body" == *"## PR Review Status"* || "$body" == *"## Re-check After"* ]]; then
        if [[ "$body" != *"Head SHA: \`$head_sha\`"* && "$body" != *"Head SHA: $head_sha"* ]]; then
            echo "openshell-agent: blocked gator review disposition without the exact current Head SHA for $owner/$repo#$number" >&2
            return 22
        fi
        if [[ "$body" != *"Gator payload: \`$GATOR_PAYLOAD_VERSION\`"* && "$body" != *"Gator payload: $GATOR_PAYLOAD_VERSION"* ]]; then
            echo "openshell-agent: blocked gator review disposition without Gator payload version $GATOR_PAYLOAD_VERSION" >&2
            return 22
        fi
    fi
}

if [[ "${OPENSHELL_GATOR_ALLOW_SAME_SHA_COMMENT:-}" != "1" && "${method^^}" == "POST" ]]; then
    request_body="$(read_body)"
    if [[ "$endpoint" =~ ^repos/([^/]+)/([^/]+)/issues/([0-9]+)/comments$ ]]; then
        guard_duplicate_gator_disposition "${BASH_REMATCH[1]}" "${BASH_REMATCH[2]}" "${BASH_REMATCH[3]}" "$request_body"
    elif [[ "$endpoint" =~ ^repos/([^/]+)/([^/]+)/pulls/([0-9]+)/reviews$ ]]; then
        guard_duplicate_gator_disposition "${BASH_REMATCH[1]}" "${BASH_REMATCH[2]}" "${BASH_REMATCH[3]}" "$request_body"
    fi
fi

exec "$REAL_GH" "$@"